Pressure responsive signal device



March 20, 1956 MULLER 2,739,201

PRESSURE RESPONSIVE SIGNAL DEVICE Filed Nov. 16, 1955 Fig.3

Alfred A. Muller INVENTOR.

United States Patent PRESSURE RESPONSIVE SIGNAL DEVICE Alfred Muller, Fowler, Ind. Application November 16, 1953, Serial No. 392,343 2 Claims. (Cl. 200-83) This invention relates to a pressure responsive signaling device and more particularly to means responsive to fluctuations in the level.

The primary object of this invention resides in the provision of means closing an operative electrical circuit to provide an audible or visable signal as may be desired when gas pressure falls below a particular predetermined level. The device is especially adapted for use in installations for bottling carbonated drinks utilizing carbon dioxide since the carbon dioxide content of the finished product must be maintained within a particular minimum tolerance.

The construction of this inventionfeatures a movable contact attached to a diaphragm which is held out of engagement with a fixed contact by the particular gas pressure which the device is set to monitor. Resilient means of novel construction are utilized for adjusting the diaphragm and hence the movable contact to close only when the gas pressure falls below the particular level at which the device is adjusted.

Still further objects and features of this invention reside in the provision of a pressure responsive signal switch that is strong and durable, simple in construction and manufacture, capable of being readily and easily adapted for a variety of uses, and which is inexpensive to produce.

These, together with the various ancillary objects and features of the invention which will become apparent as the following description proceeds, are attained by this pressure responsive signal switch, a preferred embodiment of which has been illustrated in the accompanying drawings, by way of example only, wherein:

Figure 1 is a perspective view of the device comprising the present invention;

Figure 2 is a vertical sectional view as taken along the plane of line 2-2 in Figure 1;

Figure 3 is a sectional detail view as taken along the plane of line of 3-3 in Figure 2; and

Figure 4 is a schematic circuit diagram illustrating one manner in which the device can be utilized.

With continuing reference to the accompanying drawings wherein like reference numerals designate similar parts throughout the various views, reference numeral generally designates the pressure responsive signal switch comprising the present invention which includes a main body 12 having an inlet opening 14 for connection with a gas line 16 adapted to supply gas under pressure. The main body 12 is internally threaded as at 18 for threaded reception of a cap 20 having a cylindrical extension 22 within which a fixed contact 24 is emplaced, the fixed contact 24 being insulated by means of a filler 26 from the cap 20 and thus the body 12 and the rest of the switch 10. Cylindrical guides 28 are integrally formed with the cap 20 and a suitable gasket 30 is positioned between the shoulder 32 on the cap 20 and the body 12. It is noted that the fixed contact 24 may pressure of a gas below a particular be threaded so that it may be adjusted within the filler 26 if such is at any time desired.

Attached to the body 12 by soldering or by any other means is a diaphragm 34 of any suitable material which has aflixed thereto a tubular movable contact 36 which has a contact tip 38 adapted to be received between the cylindrical guides 28 and which is adapted to engage the fixed contact 24 under certain circumstances. The use of the tubular movable contact 36 is highly desirable since such beneficially afiects the sensitivity of the switch 10 inasmuch as the tubular contact 36 engages a portion of the diaphragm 34 spaced from the center thereof at a portion of the diaphragm where displacement of the diaphragm portion most closely approximates a linear function with respect to stress applied thereto. Further, the tubular contact 36 occupies a substantial part of the chamber and thereby reduces the area of the diaphragm on which gas pressure can be exerted, thus additionally increasing sensitivity.

The body 12 is externally threaded as at 38 for threaded reception of a spring housing 40 which has an adjusting screw 42 provided with a knurled operating handle 44 threadedly secured therein. The adjusting screw 42 is provided with a conical shaped head 46 adapted to seat within a conical recess 48 formed in a floating collar 50 of stepped cylindrical construction thus forming the shoulders 52 and 54. Another collar 56 of stepped cylindrical construction having shoulders 58 and 60 is bonded or otherwise afiixed to the diaphragm 34 on the opposite side of the tubular movable contact 36 thereby assuring against uneven strain along the diaphragm 34 to such a degree as would likely rupture the diaphragm 34. Secured on the collars 50 and 56 and engaging the shoulders 52 and 58 is an outer coil spring 62 while an inner coil spring 64 is engaged on the collars 50 and 56 seated on the shoulders 54 and 60, the inner spring 64 forming means for retaining and mounting the spring 62 which is coaxial therewith.

Incorporated with the switch 10 is of course a suitable source of electrical current such as is indicated at 70 which is connected by a suitable conductor as at 72 to any portion of the body or switch insulated from the fixed contact 24 by means of the filler 26. Another conductor 74 is connected to a signal device such as a lamp as illustrated at 76 or to an audible signaling device such as a buzzer or bell, not shown, which is thence connected by any other suitable connector 78 to the source of power 70. Hence, when the movable contact 36 engages the fixed contact 24 an operative electrical circuit from the source of power 70 to the signal device 76 will be attained.

In use, gas will enter through the passage 14 under pressure thus exerting a pressure on the diaphragm 34 tending to force the contacts 36 and 24 apart. With the pressure in the gas line at a desired value, the adjusting screw 42 is turned until the external force on the diaphragm 34 caused by the springs 62 and 64 is great enough to overcome the force exerted by the gas. The contacts 36 and 24 will then be closed completing the operative electrical circuit. When the indicator 76 signals the closing of the contacts 36 and 24 external pressure on the diaphragm 34 may then be decreased by backing off the adjusting screw 42 until the indicator or alarm 76 no longer operates. At this point the pressure exerted by gas is just great enough to hold the contacts 36 and 24 apart. If gas pressure falls below this point the force exerted by these springs 62 and 64 will overcome the force exerted by the gas and the contacts 36 and 24 will close.

From the foregoing, the construction and operation of the device will be readily understood and further explanation is believed to be unnecessary. However, since numerous modificationsand changes will readily occur to those skilled in the art, it is not desired to limit, the,

invention to the exact construction shown and described, and accordingly all suitable modifications and equivalcntsmay be, r'esortedto,.failing withinthe scopeofithe appended claims. What isciaimed as new. is as follows; i 1 1., A gas pressure responsive signal device comprising amain body forminga chambensaid body having .a gas inlet opening therein, a cap vhaving an insuiated fixed contact mounted therein, said cap being detachably secured to said body, a diaphragmvsecured to said body having a'movable contact secured thereto in opposition to said fixedccntact, a spring housing. threaded-1y detachably, secured to said body, an adjusting screw a main body forming a chamber, said body having a gas inlet opening therein, a caphaving an insulated fixed contact mounted therein, said cap being detachably se- V cured to said body, a diaphragm secured to said body havinga movable contact. secured thereto in opposition to said fixed contact, a spring housing threadedly detachably secured to said body, an adjusting screw threadedly detachably secured through said spring housing, said adjusting screw having a conical-shaped end, a first collar fixed to said diaphragm, a second collar freely floating in said spring housing engaged by said adjusting screw, and resilient means biasing said first and secondcollars and extending therebetween, said first and second collars being of stepped cylindrical shape having pairs of shoulders, said resilient means including inner and outer coil springs coaxial with each other and'enga-ging'said collars about said shoulders, said, second collar having a conical recess therein adapted to receive said conicalshaped end of said adjusting screw, said movable contact having a tubular portion occupying a substantial part of said chamber.

References Cited in the file of this patent UN STATES PATENTS 2,069,222 Creamer Feb. 2, 1937 2,421,797 Malone, June 10, 1947 2,445,756 Bean July 27, 1948 2,468,768 Malick May 3, 1949 2,514,632 Flubacker July 11, 1950 

